Depending on how you do it, it could be very cool. If you were looking for a less-sour beer, you could pitch the saison yeast, let it do its thing, then add the 655.

However, if you want a relatively sour beer, I would think that adding the 565 at the same time as the 655 would be a waste of the 565...given that the 655 already has a belgian ale yeast in the mix, I don't know if the 565 would really add that much to the beer.

I just did one with Saison 568 and Brett Lambic blend (which I had sitting around)... I need to bottle it soon... but as said earlier it is missing quite a bit of the "saison-esque" esters and phenols.